Broker Limits and Behaviors

The message throughput that a broker might be required to handle is
a function of the use patterns of the messaging applications the broker supports.
However, the broker is limited in resources: memory, CPU cycles,
and so forth. As a result, it would be possible for a broker to become overwhelmed
to the point where it becomes unresponsive or unstable.

The Message Queue message broker has mechanisms built in for managing
memory resources and preventing the broker from running out of memory. These
mechanisms include configurable limits on the number of messages or message
bytes that can be held by a broker or its individual physical destinations,
and a set of behaviors that can be instituted when physical destination limits
are reached.

With careful monitoring and tuning, these configurable mechanisms can
be used to balance the inflow and outflow of messages so that system overload
cannot occur. While these mechanisms consume overhead and can limit message
throughput, they nevertheless maintain operational integrity.